The present application is a National Stage Application of International Application No. PCT/EP00/06157, filed Jul. 4, 2001. Further, the present application claims priority under 35 U.S.C. xc2xa7 119 of German Patent Application No. 199 30 802.0 filed on Jul. 3, 1999.
1. Field of the Invention
The invention relates to a cartridge for magnetic recording media in tape form, preferably a single-reel cartridge for data tapes having a multi-part braking system.
2. Discussion of Background Information
Cartridges of this type comprise at least a housing which, with the exception of one corner, is of an angular design. The housing has two housing parts with bottom, top and side walls and the housing parts are welded or screwed to one another. A tape reel is provided which uses a hub. Protruding from the ends of the hub are radial upper and lower flanges. The hub base has the driving and braking serration, and a magnetic tape (not shown) is wound up on the hub. Provided at the free end of the hub is a guide element. With the aid of the guide element, the magnetic tape is led to the winding-up reel and wound up on the latter. A reel brake is also included, which is connected on its upper side via connecting elements to the housing top wall in an axially displaceable manner. However, it is secured against twisting and radial positional changes. The serration engages in the braking serration of the tape reel and thus also secures the tape reel against twisting and, by the action of the spring, simultaneously presses against the lower housing part when the driving hub of the equipment is not in engagement.
The reel brake 1, which is generally conventional in the case of single-reel cartridges, is released directly, as shown in FIG. 1 and FIG. 2, on the equipment side by a pin 2 having a wear-resistant surface. Since the surface of this pin 2 protrudes somewhat above the plane of the serration 6 of the driving hub or the winding pin 8, the reel brake 1 is initially lifted against the force of the spring 12 by the winding pin 8 during loading of the cartridge into the drive unit. Only thereafter does the force acting between the magnet 9 on the equipment side and the metal plate 10 recessed into the hub base of the tape reel 3 cause the serration 6 of the winding pin 8 to engage in the driving serration 5 of the tape reel 3 and cause the tape reel 3 to be lifted from the lower wall of the housing 7 out of its first position, (i.e., the rest position shown in FIG. 1), into its second position, (i.e., the operating position), which is shown in FIG. 2.
EP 0 284 687 A describes a single-reel cartridge with improved centering of the reel brake relative to the tape reel. The ribs or projections are mounted about the cylindrical inner circumference of the tape reel hub, on which the exterior diameter of the disk-shaped center of the reel brake is guided, both when assembling the cartridge and when easing the reel brake during operation.
This type of braking system has, among other disadvantages, the disadvantage that both the required travel for releasing the reel brake and the travel for lifting the tape reel out of its first position into its second position are added to each other and consequently restrict the lower limit of the cassette height and overall equipment height.
EP 0 926 676 A describes a single-reel cartridge with two-part braking system, with the first part of the braking system being operated by the equipment-side driving hub, and having on the circumference of its disk-shaped central portion an annular protrusion pointing in the direction of equipment-side driving hub, which protrusion extends into a circular groove located in the area of the tape reel hub opening, and with the circumferential circular protrusion overlapping the circumferential circular groove even with the travel of the braking system necessary to release the reel brake, and with the cartridge thus being protected from dust and dirt entering through the reel hub opening.
However, technical development has for some time required cartridges with an every greater storage density and at the same time every smaller outer housing dimensions.
A braking system which meets this requirement is conventionally known. This system is represented in FIG. 3 and proposes a two-part braking system, the first element corresponding to the conventional reel brake 1 and the second element representing a driver disk 4. The driver disk 4 includes a thin plate 11, which is axially displaceable within the hub 13 and has three feet 14 which are evenly distributed around the circumference and protrude through the hub base of the tape reel 3, through clearances 16 in the region of the driving serration 5. The releasing of the reel brake 1 from the tape reel 3 in the operating position (i.e., the second position) thus takes place by means of this driver disk 4, which is lifted to the same extent in the tape reel as the serration 6 of the driving hub 8 engaging into the driving serration 5 of the tape reel 3 when the forces of the magnet 9 act on the metal plate 10 fastened in the tape reel 3.
A disadvantage of this arrangement is that it only functions satisfactorily if the tolerances between the driver disk 4 and clearances 16 of the tape reel 3 are adequate in the corresponding regions. This results in both radial and tangential backlash and consequently in moveability or movement between the driver disk 4 and tape reel 3.
Since the tape reel 3 constantly undergoes changes of direction and accelerations during operation, forces of inertia act on the driver disk 4, making the driver disk 4 run eccentrically within the tolerances in the tape reel 3.
To be regarded as another disadvantage of the known cartridges is the configuration of the contact surfaces between the reel brake 1 and driver disk 4. Adequately precise concentric running of the tape reel 3 can be achieved only if the reference receiving openings 17 for positional fixing of the cartridge in the equipment and the centering on axis A of the tape reel 3 with respect to the centering of the reel brake 1 lie within relatively small tolerances. For example, it is possible that, owing to the radial moveability or movement of the driver disk 4 within the tape reel 3, the contact surface of the reel brake 1 can over time work into the surface of the driver disk 4 at various points, which may be further exacerbated by differences in the positional fixing when playing back the magnetic-tape cartridge on different equipment. This may result in eccentric centerings between the reel brake 1 and driver disk 4, which bring about undesired radial movement of one or both parts 1 and 4 in their guides during each revolution.
A further disadvantage of conventional braking systems is the fact that the reel brake 1 has a tendency to undergo wobbling movements if runout errors of the tape reel 3, caused by tolerances originating both from the equipment and from the tape reel itself, coincide with correspondingly great backlash in the elements of the twist-preventing means of the reel brake 1.
Furthermore, during the transfer of the force of the spring 12 by the reel brake 1 to the feet 14 arranged on the outer circumference of the plate 11, the thin plate 11 of the driver disk 4 can bend and thus reduce the brake lifting-out path.
As a consequence of this, running noises and abrasion occur at the driving serration 6 and/or driver disk 4 and/or cartridge housing 7.
Abrasion generally produces dropouts on the recording medium in tape form. Abrasion at the driver disk 4 and at the serration 5 causes dimensional changes at the parts concerned and, in an extreme form, may reduce the brake lifting-out path and consequently make the cartridge unable to function.
Since both running noises and abrasion cannot be accepted for high-quality digital data storage systems, the object was to improve the braking system in such a way that the disadvantages described above, such as restricted functional reliability and running noises, due to impermissible moveability of the cassette components, and a high dropout rate due to abrasion, are eliminated.
The invention therefore provides a magnetic-tape cartridge which includes a substantially rectangular housing, at least one tape reel which is rotatably mounted therein and on which magnetic tape is wound up, and a multi-part braking system, at least one part being mounted in the center of the tape reel and at least a second part being spring-mounted on a housing wall, in each case in a torsionally secure and axially displaceable manner, and a first part, on the equipment side, being lifted from a rest position into an operating position and thus releasing a second part against the action of the force of the spring, out of its positive connection with the tape reel, and at least one part having flexible mechanisms, by which it is releasably fixed, at least in the operating position, on corresponding guiding mechanisms of the tape reel and/or of the cartridge housing.
The invention provides for a magnetic-tape cartridge, comprising a substantially rectangular housing, at least one tape reel which is rotatably mounted therein and on which magnetic tape is wound up, and a multi-part braking system, at least one part being mounted in the center of the tape reel and at least a second part being spring-mounted on a housing wall, in each case in a torsionally secure and axially displaceable manner, and a first part, on the equipment side, being lifted from a rest position into an operating position and thus releasing a second part against the action of the force of the spring, out of its positive connection with the tape reel, wherein at least one part has a flexible mechanism, by which it is releasably fixed, at least in the operating position, on corresponding guiding mechanisms of the tape reel and/or of the cartridge housing.
The first part may be designed as a driver disk, comprising a circular central plate, the cross section of which is preferably of a conical design and the upper side of the plate is rounded off in the central region, which forms the contact surface with respect to the reel brake, and a plurality of, preferably three, feet evenly distributed over the circumference of the central plate and extending in the axial direction. The second part may be designed as a reel brake, the face lying opposite the driver disk being planar, at least in the region of the contact surface. Preferably on the upper outer edge of the reel brake there are arranged regularly distributed or continuous, thin-walled flexible elements, which in the upper end position of the reel brake come to bear against a preferably peripheral rib of the upper housing part. The feet are of a T-shaped design and are preferably connected centrally to the central plate by way of radial connecting elements. The connecting elements may have a cross-sectional reduction. The T-bars of the feet of the driver disk may have planar guiding mechanisms, which preferably at the ends run in opposite senses with respect to one another, preferably obliquely toward the center axis, and are guided in a sliding manner on correspondingly beveled guiding mechanisms of the tape reel. The reel brake and/or the driver disk include a wear-resistant plastic. The wear-resistant plastic at least of one part may be mixed with at least one friction-reducing additive. The sum of the frictional forces, caused by the flexible fixing, between the braking parts, the guiding mechanisms of the tape reel and driver disk, the ribs and the guides, the flexible spring element and the peripheral housing rib of the braking part or cartridge housing may be less than the minimum force of the spring acting on the braking part.
The invention also provides for a magnetic-tape cartridge that includes a substantially rectangular housing. At least one tape reel is rotatably mounted in the housing. The at least one tape reel is configured to receive wound magnetic tape. A first part is axially movably mounted in a center of the at least one tape reel. A second part is non-rotatably mounted and axially movably mounted to a housing wall of the cartridge via a spring. The first part is movable between a resting position and an operating position in which the first part moves the second part against the biasing force of the spring. The second part is movable between a first position, thereby preventing the at least one tape reel from rotating, to a second position thereby allowing rotation of the at least one tape reel.
The second part may comprise a flexible mechanism. The first part may comprise a flexible mechanism. The at least one tape reel may comprise one of guiding surfaces and guiding mechanisms which cooperate with the flexible mechanism. The at least one tape reel may comprise one of guiding surfaces and guiding mechanisms. The first part may comprise a driver disk that includes a circular central plate and a contact surface. The circular central plate may have a conical surface. The contact surface may be one of curved or rounded. The driver disk may include a plurality of feet which are evenly distributed over a circumference of the circular central plate, wherein the feet extend in an axial direction. The second part may comprise a reel brake and a contact surface. The reel brake may comprise a planar face which is engagable with the first part. The reel brake may comprise at least one thin-walled flexible element. The at least one thin-walled flexible element may be engagable with a peripheral rib projecting from the housing wall of the cartridge. The driver disk may include a plurality of feet which are evenly distributed over a circumference of the circular central plate, wherein the feet extend in an axial direction and are T-shaped. The feet may be connected centrally to the circular central plate by radial connecting elements. The connecting elements may comprise a cross-sectional reduction. The feet may comprise T-bars. The T-bars may comprise one of planar guiding mechanisms and planar guiding surfaces. The planar guiding mechanisms or surfaces may be angled obliquely toward a center axis. The at least one tape reel may comprise one of planar guiding mechanisms and planar guiding surfaces which engage the T-bars. The at least one of the first part and the second part may comprise a wear-resistant plastic. Each of the first part and the second part may comprise a wear-resistant plastic. The wear-resistant plastic may comprise a mixture which includes at least one friction-reducing additive.
The invention also provides for a magnetic-tape cartridge comprising a housing. At least one tape reel is rotatably mounted in the housing. The at least one tape reel comprises a braking serration and is configured to receive wound magnetic tape. A driver mechanism is axially movably mounted. A reel brake comprises a braking serration and is non-rotatably and axially movably mounted within the housing via a biasing mechanism. The driver mechanism is movable between a resting position, in which the braking serration of the reel brake is allowed to engage the braking serration of the at least one tape reel, and an operating position, in which the driver disk moves the reel brake against the biasing force of the biasing mechanism and thereby dis-engages the braking serration of reel brake from the braking serration of the at least one tape reel.
The invention also provides for a magnetic-tape cartridge comprising a housing. At least one tape reel is rotatably mounted in the housing. The at least one tape reel comprises a braking serration and recesses, and is configured to receive a wound magnetic tape. A driver mechanism comprises radially oriented extensions and is axially movably mounted within the at least one tape reel. The radially oriented extensions are movably disposed in the recesses and each having an axially oriented part. A reel brake comprises a braking serration and is non-rotatably and axially movably mounted inside the cartridge via a biasing mechanism. The driver mechanism is movable between a resting position, in which the braking serration of the reel brake is allowed to engage the braking serration of the at least one tape reel, and an operating position, in which the driver disk moves the reel brake against the biasing force of the biasing mechanism and thereby dis-engages the braking serration of reel brake from the braking serration of the at least one tape reel.